In TFT-LCD (Thin Film Transistor—Liquid Crystal Display), the basic principle of displaying a frame of image is to output the signals required by every row/line of pixels from top to bottom in turn via source driving, and input square waves of certain width to every pixel row/line from top to bottom in turn for enabling via gate driving.
As shown in FIG. 1, an existing shift register applied to a liquid crystal display gate driving apparatus comprises a pre-charge unit T1, a pull-up unit T3, a reset unit T2 and a pull-down unit T4. Node P (the node that is connected to the source of T1) is connected to a clock signal CLK1 via a capacitor C1, the drain of T3 is connected to a clock signal CLK2, node P is connected to the source of T3 via a capacitor C2, and Voff may be either zero or low potential (e.g. GND or VSS power supply). When the output signal Input(n-1) of a pre-stage shift register is at high level, T1 pre-charges node P (the node connected to the source of T1); T3 collaborates with the timing of CLK2 so that the output signal Row(n) of the current stage shift register is at high level; when the output signal Reset(n+1) of the next-stage shift register is at high level, T2 resets the control end of T3, T4 resets the output signal Row(n) of the current stage shift register. When the output signal Reset(n+1) of the next-stage shift register is at low level, the control end and output of T3 are floating, which results in the instability of the output signal Row(n) of the current stage shift register.
Furthermore, the current manufacturing method uses the COG (Chip On Glass) technique to adhere gate driving IC and source driving IC onto a glass panel. In the case of small-sized TFT-LCD, when the resolution is relatively high, the gate driving and source driving may output more, and the length of driving IC may increase, which would be disadvantageous to the bonding technique of module driving IC.